Wellhead closure apparatus



Oct. 28, 1969 I N. a. NEWMAN ETAL 3,474,857

WELLHEAD CLOSURE APPARATUS Original Filed July 30, 1959 5 Sheets-Sheet 1 i j :k I8 24 v v Q L INVENTORS:

N. B. NEWMAN K. w. FOSTER R. L. GEER BY: FIG. I '2 dJIJ C 1 20 THEIR AGENT Oct. 28, 1969 N, NEWMAN ET AL 3,474,857

WELLHEAD CLOSURE APPARATUS Original Filed July, :50, 1959 5 Sheets-Sheet 2 INVENTORSI N. B. NEWMAN K. W. FOSTER R. L. GEER THE R, AG NT 1969 I N. a. NEWMAN ETAL WELLHEAD CLOSURE APPARATUS Original Filed July so, 1959 5 Sheets-Sheet s I 5Q it,

INVENTORS:

N. B. NEWMAN K. W. FOSTER- R. 1.. GEER B 61 "Iva-2%. Hum AGENT Oct 28, 9 N. B. NEWMAN ETAL I 3,474,857

WELLHEAD CLOSURE APPARATUS Original Filed July so, 1959 5 Sheets- Sheet 4 INVENTORSI N. B. NEWMAN K. W. FOSTER R. L. GEER 5 Sheets-Sheet 5 N.,B. NEWMAN ETAL WELLHEAD CLOSURE APPARATUS 4 FIG TIA Original Filed July 50, 1959 m W M 6i V 11 i r z I w a fig 1- /L\ \\v v A 097/ N// 4/ w/ m m m m a m m m m a? m m u m m Oct. 28, 1969 N R T AF- C N SW MG m m m 5 United States Patent 3,474,857 WELLHEAD CLOSURE APPARATUS Nicholas B. Newman and Kenneth W. Foster, Houston, Tex., and Ronald L. Geer, Metairie, La., assignors to Shell Oil Company, New York, N.Y., a corporation of Delaware Continuation of application Ser. No. 830,587, July 30, 1959. This application Aug. 16, 1962, Ser. No. 218,482 Int. Cl. E21b 33/035 US. Cl. 166.5 27 Claims The present apparatus relates to oil well equipment for use at underwater locations and pertains more particularly to a wellhead closure apparatus for closing the top of a wellhead assembly in a fluid-tight manner While protecting it from the harmful effects of salt water and marine life encountered at offshore locations.

The presentapplication is a continuation application of copending patent application, Ser. No. 830,587, filed July 30, 1959, now abandoned.

The wellhead closure of the present invention is adapted to be used to close wellhead assemblies of the type found in copending application, Ser. No. 830,538, filed July 30, 1959, now Patent No. 3,256,937, issued June 21, 1966. A recent development in the field of oil well drilling is the completion of wells at offshore locations with the Wellhead assembly positioned on or close to the ocean floor out of the way of ships which may damage it in the event of a collision. Equipment on the ocean floor, however, faces problems such as the corrosive nature of the sea water and the presence of marine life which tends to grow and become encrusted on metallic structures below the surface of the water.

Since it is necessary from time to time to go back into a well wherever it has been completed, it is desirable to have an underwater wellhead structure in suitable condition so that pieces of equipment can readily be lowered from the surface of the water and attached to the wellhead structure. It is therefore a primary object of the present invention to provide a wellhead closure apparatus by which an underwater wellhead assembly may be entered for the purpose of carrying out workover operations in the well.

A further object of the present invention is to provide suitable connecting means by which equipment can be lowered from the surface of the water into engagement with metallic surfaces of an underwater wellhead, which surfaces have been protected against exposure to the sea water and to marine life.

Another object of the present invention is to provide an apparatus for normally closing the top of a Wellhead assembly while providing means for direct vertical access into the well to carry on workover operations therein.

A still further object of this invention is to provide a well closure apparatus including valves and fluid manifold means whereby tubing strings may be connected to the wellhead assembly through the closure means to actuate any of the various components of the wellhead assembly.

These and other objects of the present invention will be understood from the following description taken with regard to the drawing, wherein:

FIGURE 1 is a schematic view illustrating several of the components which may be arranged as an underwater wellhead assembly.

FIGURE 2 is a longitudinal view taken partially in cross-section of the wellhead closure of the present invention;

FIGURE 3 is a cross-sectional view taken along the line 33 of FIGURE 2;

ice

FIGURE 4 is a longitudinal view taken in crosssection of the wellhead closure of FIGURE 3 with a running string, running head and tubing strings attached thereto;

FIGURE 5 is a longitudinal view taken in cross-section of the wellhead closure of FIGURE 2 when taken in a view degrees thereto;

FIGURE 6 is a cross-sectional view taken along the line 66 of FIGURE 7;

FIGURES 7 and 7A are a longitudinal view taken in cross-section showing the valve and manifold system of FIGURE 5 in enlarged detail; and

FIGURE 8 is a cross-sectional view of another type of closure plug for sealing the top of the present wellhead apparatus.

Referring to FIGURE 1 of the drawing a wellhead assembly or production control unit for an offshore well completed underwater is shown as comprising a closure apparatus 11 for closing the top of a well casing 12 and securing the wellhead assembly thereto, the wellhead assembly comprising a group of power-actuated components including flow line control valves 13, 14, 15 and 16, swabbing valves 17 and 18, an electro-hydraulic package unit 21 containing a motor, reservoir and pump, and a second package unit 22 containing the various controlling pilot valves which are preferably solenoidactuated. The entire wellhead assembly may be encased in a container 23. The wellhead assembly may be provided with a pair of hydraulic pressure lines 24 and 25 which extend through the wall of the container 23 to operate a well component such, for example, as a flow line connector shown and described in copending patent application, Ser. No. 835,931, filed Aug. 15, 1959, now abandoned. The casing closure unit 11 and the wellhead assembly hold-down unit are described in greater detail in copending application Ser. No. 830,538, filed July 30, 1959. The present invention is concerned with a closure apparatus 26 for closing the top of an underwater wellhead assembly and permitting re-entry thereto in order to service or perform other operations on the well.

A wellhead closure apparatus 26, in accordance with the present invention, is shown in FIGURE 2 as comprising an elongated cylindrical housing or body member 30 having a flange 31 adapted to be bolted to a flange 32 (FIGURE 1) fixedly secured to the container 23, or to the wellhead assembly contained therein. Other suitable means for connecting the wellhead closure apparatus to the wellhead assembly may be employed in place of flange 31.

One or more vertical conduits, such for example as conduits 33 and 34 of FIGURE 2, extend through the entire length of the closure means body member 30 and are in fluid communication with tubing strings 19 and 20 which depend within the well casing 12. These conduits 33 and 34 are preferably provided with one or more seating shoulders or annular recesses such as those illustrated by numerals 35-48 whereby various tools, valves and/or other devices may be definitely positioned at various points therein.

Extending through the side wall of the body member 30, preferably near the lower end thereof, are side conduits 51 and 52 in communication between the vertical conduit 33 and 34 and the space outside the body member 30. The ends of the conduits 51 and 52 terminating in the vertical conduits 33 and 34 are normally closed by suitable valves, such for example as slidable sleeve valves 53 and 54 having openings 55 and 56, respectively, therein, which openings are adapted to register with the conduits 51 and 52 when the valves 53 and 54 are in their open position. Either the outer wall of the valves 53 and 54 or the inner wall of the vertical conduits 33 and 34 which they contact, are provided with suitable O-ring seals. The valves 53 and 54 may also be provided with positioning rings 61 and 62 which keep the valves anchored in the position which they are set.

Valves of this particular design are well known to the oil field art and may be moved from their open to closed positions by various sleeve valve shifting tools which may be run down into a well on a string of pipe or a wire line. A typical sleeve valve shifting tool is shown and described in FIGURES 2, 3 and 4, page 1976 of the 1957 edition of Composite Catalog of Oil Field Equipment and Services, published by World Oil. The valves 53 ad 54 themselves are preferably of the fullbore type, that is, the bores 63 and 64 of the sleeve valves 53 and 54 are at least equal to the inner diameter of the tubing strings used in the well.

The other ends of the side conduits 51 and 52, that is, the ends of the conduits terminating at the outer surface of the body member 30, are adapted to be connected to other conduits 65 and 66 which lead to any of the various power-fluid-actuated components, such as valves, holddown devices, etc., employed in the wellhead assembly as those found in copending application, Ser. No. 830,- 538, filed July 30, 1959. A typical well head control valve 13-14 (FIGURE 1) is shown and described in the 1957 Composite Catalog, page 5277 as a WKM Company valve R5008NHD66 having any suitable type of a hydraulic operator on it such for example as those on page 4964 of the 1957 Composite Catalog of Oil Field Equipment, manufactured by Joe Stine Company, which operators are remotely controlled.

The top of the body member 30 may be recessed, as at 70. The recess 70 is provided to receive a suitable plug 71 having at least a portion of the outer surface made of rubber whereby a fluidtight seal is formed between the plug 71 and the inner wall of the body member 30 within the recess 70 so that the top of the one or more vertical conduits, for example, 33 and 34, passing down through the body member, are closed in a fluidtight manner. Preferably, the plug member 71 is provided with dogs or fingers 72 which are preferably spring-loaded and adapted to seat within recesses 73 in the inner surface of the wall of the body 30. The construction of a preferred plug for sealing the upper end of a body member of the present invention is described in detail in copending application Ser. No. 830,538, filed July 30, 1959. It is to be understood that rather than forming the recess 70 in the top of the body member 30 to receive a plug 71, a cap-type plug may be employed instead which fits down over the outside of the top of the body member 30 to seal the top of the body in a fluidtight manner. The lower edge of a cap-type closure member may seat in an annular recess 74 which is normally provided to receive the locking dogs of a device for lowering the present wellhead closure member together with the entire wellhead assembly down into place in the top of a well casing, as will be described hereinbelow.

In a preferred embodiment of the present invention the body member may be provided with one or more grease ports 75 and 76 in communication with the conduits 33 and 34 above slide valves 53 and 54 and the space outside the body member 30. Additional grease ports 77 and 78 are shown as communicating with grease channels 79 and 80 which pass down through the body member 30.

If desired, auxiliary means for shutting the conduits 33 and 34 may be provided by employing a pair of tubing plugs such as those known as Type S tubing plugs, manufactured by Otis Engineering Company. A typical plug 83 is shown positioned in conduit 33 and comprises a body member having packing rings 84 and 85 mounted thereon to seal against the inner wall of the conduit 33. The

tubing plug 83 is also provided with one or more sets of locking dogs 86 adapted to expand radially into annular recess 37 in the body member 30 to lock the tubing plug 83 in place. The dogs 86 may be retracted by running an overshot tool on a wire line down to engage the fishing head 87 at the top of the tubing plug 83. An upward pull on the fishing head 87 causes the dogs 86 to retract in a manner well known to the art, thus allowing the removal of the tubing plug from the conduit 33.

In the event that the outer surface of the body member 30 is provided with an annular recess 74 cut in the outer surface thereof, or any other suitable anchoring device formed on the outer surface thereof, at least the upper portion of the body member 30 is preferably encased in a temporarily removable or retractable sleeve which may act as an outer casing to minimize corrosion and the growth of marine organisms on the outer surface of the body member 30 which might prevent the orientation of a running tool head, as will be described hereinbelow. Such a protective outer casing on the body member 30 may take the form, as illustrated in FIGURE 2, of a spring-loaded bellows sleeve having a spring 90 integrally formed in a thin flexible wall 91 of a fluid-impermeable material, which, when compressed, takes the form of a bellows unit as shown in FIGURE 5. The top and bottom of the spring-loaded bellows unit 90-91 may be fixedly secured to ring members 92 and 93, the upper ring member 92 being slidably mounted in a low-pressure fluid-tight engagement with the outer surface of the body member 30. The ring members 92 and 93 may be covered with rubber or any other suitable sealing means to form a substantially low-pressure fluid-tight seal around the body member 30. The lower ring 93 may be secured against downward displacement, as by fixedly securing it to the body member 30, or allowing it to rest on a shoulder 94 thereof. The spring-loaded protective bellows unit 90-91 extends from the top of the body member 30 downwardly a distance sufficient so that in its operative position the bellows unit covers at least all of the outer surface of the body member from the top thereof to a point below the annular groove 74 to be engaged by a running head, and also extends a suflicient distance below this point so that the spring-loaded bellows may be compressed without being injured. A spring-loaded chemically inert bellows is preferred. The wall 91 of the bellows can be made of metal or any flexible rubber-like or plastic material. The ports 75, 76, 77, 78, 154 and 155 in the wall of the body member 30 provide means by which a grease may be injected into the annular space between the outer surface of the body member 30 and the inner surface of the bellows unit. This displaces any sea water which has entered.

The open upper ends of each of the bores 33 and 34 are preferably bevelled, as illustrated in FIGURE 2, to facilitate the entry of tubing strings thereinto. Additionally, if more than one vertical conduit 33 is provided in the body member 30, they may be of different diameters to facilitate the running of tubing string into the varous conduits 33 and 34 and maintain identity as to which one is connected to which tubing, to be later inserted. Thus, if vertical conduit 33 had a diameter an eighth of an inch larger than conduit 34, the larger of two tubing strings would be run into the well first to make sure that it was seated in conduit 33. If desired, one or more pins 95 and 96 may be provided which extend into the bore of each of the conduits 33 and 34, respectively, and are used to lock the lower ends of the tubings 97 and 98, thereto, as illustrated in FIGURE 4. In the event that conduits 33 and 34 are of the same size, one conduit could be provided with a single pin 95 while the other conduit could be provided with two pins in order to identify the conduit into which a certain tubing was run and locked. For ease in illustrating the present invention, only one tubing plug 83 is shown in FIGURE 2, it being understood that conduit 34 would also contain a similar plug.

In order to enter a wellhead assembly closed by a wellhead closure apparatus in accordance with the present invention a string of pipe 100 having a running head 101 secured to the lower end thereof would be lowered from a drilling barge down through the water to the ocean floor in a manner described in copending applicaton, Ser. No. 830,538, filed July 30, 1959. As the running and latching head 101 is lowered down on the top of the body member 30, which at that time would be still closed at the top by means of a plug 71 (FIGURE 2), the lower end 101a of the running head 101 comes in contact with the top ring of slidable unit 92 of the bellows unit 90-91, forcing it downwardly along the side of the body member 30. Lowering of the running head 101 continues until a skirt 102 depending from the running head 101 contacts the shoulder 94 on the outer surface of the body member 30. By providing a skirt 102 on the running head 101, damage to the bellows unit 90-91 by extreme compression is prevented. Alternatively, instead of employing the skirt 102 to limit the downward travel of the running head 101, one or more stop means 104 and 105 may be welded to the inner wall of the running head 101 to contact the upper end of the body member 30.

With the running head 101 seated on the top of the body member 30 of the present well closure apparatus, a series of locking dogs, such as illustrated at 106 and 107 are forced radially inwardly into the annular groove 74 in the body member 30. Movement of the dogs 106 and 107 is accomplished by applying a pressure fluid through conduit 110 into the annular chamber 111 above a piston member 112 carried within the housing of the lowering head 101.

A fishing tool (not shown) is run down through the marine conductor pipe string 100 (FIGURE 4) to cut through the rubber covering 113 (FIGURE 2) surrounding the fishing neck 114 of the plug 71. An upward pull on the fishing neck 114 disengages the locking dogs 72 of the plug and allows the plug to be withdrawn upwardly to the surface. In the event that the covering 113 on the fishing neck 114 is of a relatively hard material, such as a hard plastic material or a soft metal such as aluminum, an overshot tool may be run on a pipe string down to cut away the covering 113 before running the fishing tool on a wire line.

With the plug seal 71 removed, separate tubing strings 97 and 98 (FIGURE 4) are run into conduits 33 and 34 and locked onto pins 95 and 96. A wire-line fishing tool is then run down through the tubing strings 97 and 98 and into the conduits 33 and 34 to remove the tubing plugs 83 therefrom, in a manner similar to the removal of plug 71. A wire-line valve-shifting tool, well known to the art, is then lowered from the drilling barge on the surface, through tubing 97 to contact sleeve valve 53 and move it downwardly so that its port 55 is in register with the end of conduit 51. Simultaneously, or subsequently, another valve-shifting tool is lowered through tubing string 98 to move sleeve valve 54 so that its port 56 can register with conduit 52.

With both sleeve valves 55 and 56 open, a pressure fluid may be pumped down through tubing string 97, conduit 33, and side conduit 51 to furnish an actuating pressure fluid to any of the many pressure-actuated components of an underwater well head described in copending application, Ser. No. 830,538, filed July 30, 1959. During this operation conduit 66 (FIGURE 2), side conduit 52, vertical conduit 34 and tubing string 98 serve as a return line for the pressure fluid, or as a release line for pressure fluid on the other side of the component being actuated. After the necessary operation of operating one of the wellhead pressure-actuated components has been carried out, the valve-shifting tools are again lowered to close valves 53 and 54. With the valve-shifting tools withdrawn from the tubing string 97 and 98, it may be seen that a pair of vertical conduits through tubings 97 and 98 and conduits 33 and 34 are provided whereby tools may be run down through the well head and tubing systerns of the well installation when the well head control valves are open, so as to carry out any of the many operations within the well.

In FIGURES 2 and 4 a wellhead closure apparatus in accordance with the present invention is shownas being provided with a pair of vertical conduits 33 and 34, each being connected to the single side conduit 51 and 52, respectively. With this apparatus a single wellhead component could be opened or closed if a relief line is needed from the pressure-actuated component. However, if the wellhead components are arranged, through suitable spring-loading or other means, for maintaining a fixed position while being pressure-'actuatable to a second position, the wellhead closure apparatus of FIGURES 2 and 4 is designed to supply two different pressure fluids, one to each of the two components of the wellhead. It will generally be found however that a self-contained underwater wellhead assembly will contain several components, thus requiring a more complicated well closure apparatus than that illustrated in FIGURES 2 and 4.

Another embodiment of the present wellhead closure apparatus is shown in FIGURE 5. Actually, by referring to FIGURE 3 of the drawing it may be seen that the apparatus of FIGURES 4 and 5 may be combined by the proper location of the various vertical conduits, FIGURE 5 being a view taken in longitudinal cross-section in a plane degrees to that shown in FIGURE 4. While it is preferable to have a pair of vertical conduits 33 and 34 extend entirely through the wellhead closure apparatus, as shown in FIGURES 2 and 4, in order to permit entry into the well, it is realized that some wellhead closures need not permit entry into a well, but merely permit the connection of pressure-fluid tubing strings to various wellhead components,

Referring to FIGURE 5, the elongated cylindrical body member 30 of the present apparatus is shown as being provided with a second pair of vertical conduits 115 and 116 which extend a substantial length thereof. Near the lower end of vertical conduit 115 a pair of side conduits 117 and 118 extend through the side wall of body member 30 while another pair of side conduits 119 and 120 are in communication through the side wall of body member 30 with the vertical conduit 116.

The vertical conduits 115 and 116 are provided with spring-loaded slide valves 123 and 124, respectively. Compression springs 125 and 126 urge the valves 123 and 124 upwardly against positioning pins 127 and 128 which extend inwardly into the bore of the vertical conduits 115 and 116.

In FIGURE 7 a valve and manifolding system for one of the conduits, say conduit 116 is shown as comprising a pair of concentric tubes 131 and 132 closed in a fluidtight manner by a closure 133 which may be provided with O-ring seals 134. The spring-loaded valve 124 is arranged in a telescopic manner through a packing gland 135 so as to slide in and out of the innermost tube 132. The innermost tube 132 is closed at a point below the furthermost travel of valve 124 by means of a plug or other suitable means 136.

From FIGURE 6, it may be seen that a pair of radially extending partitioning walls 137 and 138 divide the space between the tubes 131 and 132 into two fluid flow passages 141 and 142. The lower end of the flow passage 141 is closed in a fluid-tight manner by a closure 143 positioned below closure 136 so that port means 144 may extend through the innermost tube 132 at a point below closure 136, thus putting the flow passage 141 in communication with the bore 145 of the inner tube 132. The lower end of the bore 145 of inner tube 132 communicates through the lower end of vertical conduit 116 with the side conduit 120. The flow passage 142 communicates in a like manner with the annular space outside the tube 132 below the closure 143, and hence through side conduit 119.

Near the top of tube 132 (FIGURE 7) a port 150 extends through the wall thereof in communication between the flow passage 141 and the interior of tube 132. A second port 151 extends through the wall of the inner tube 132 near the top thereof in communication between the flow passage 142 and the interior of the tube 132. Both ports 150 and 151 are normally closed by the slide valve 124 when it is in its uppermost position. The sleeve valve 124 is provided with two sets of ports 152 and 153 which are adapted to register with ports 150 and 151, respectively. The spacing between the ports 152 and 153 is such that only one port 150 or 151 can be opened at a time.

In operation, after a landing head 101 (FIGURE has been run on the lower end of the marine conductor 100 down to the well closure member 30 and locked in place thereon, as shown in FIGURE 5, the sealing plug 71 is removed in a manner previously described. Small diameter tubing strings are run down into the vertical conduits 115 and 116 and seated against the pins 127 and 128 therein. Each of the tubing strings has a longitudinal slot of predetermined length cut upwardly from the bottom edge of the tubing, said slot being of a width to pass over the pin 127 and 128 The length of the slot is equal to either the distance between ports 150 and 152, or between ports 151 and 153. Thus, if the tubing string (not shown) has a slot in its lower end as long as the distance between ports 151 and 153, the pin 128 will pass up the slot allowing the lower edge of the tubing string to force down the spring-loaded sleeve valve 124 until ports 151 and 153 are in register. With the same ports opened by a similar movement of sleeve valve 123 a pressure fluid could be pumped down through the tubing string, through the sleeve valve 124 out port 153 thereof, and through ports 151, thence downwardly through conduit 142, annular space 146 and side conduit 119 to actuate any pressurefluid-operated device or control member of the wellhead assembly, such as, for example, the wellhead assembly lock-down unit described in copending application, Ser. No. 830,538, filed July 30, 1959. At the same time, return fluid from the two-way flow line connector would pass in through conduit 117 and up through valve 123 and its manifold system.

Assuming for purposes of illustration that side conduit 118 (FIGURE 5) is connected to operate a spring-closed hydraulically-opened swabbing valve in the wellhead assembly (not shown), which it is desired to open. A tubing having a slot in the end equal to the distance between ports 150 and 152 would be used to push valve 123 downwardly until these ports were open. If desired, the same tubing string may have slots of different length in the end of the tubing, the slots being positioned diametrically opposite each other. Thus, for example, after releasing a flow line connector (not shown) by applying a pressure fluid down through vertical conduit 115 and side conduit 117, the tubing string could be raised a few inches and rotated 180 degrees and then lowered again to force valve 123 downwardly so that ports 151 and 153 are in register. A pressure fluid now applied through the tubing string, to vertical conduit 115, through the valve 123 and its ports 153, thence through port 151, flow passage 141, port 144 and flow passage 145 through side outlet conduit 118, to pressure a normally spring-closed valve and open it. At the same time the vertical conduit 116 and side conduit 120 could be employed to open another valve, pair of valves, or other mechanism on the wellhead assembly. Thus, it may be seen that by uniting the vertical conduits 33 and 34 of FIGURE 4 and 115 and 116 of FIGURE 5 in a single embodiment of the present invention as shown in FIGURE 3, at least three and as many as six pressureoperated components for wellhead assembly may be energized, either opened or closed, connected or disconnected, etc.

When all of the necessary operations have been carried out on the wellhead assembly (not shown), tubing strings, such as elements 97 and 98 of FIGURE 4, are withdrawn from the wellhead closure apparatus of the present invention and raised to the surface, leaving pipe string empty. The sealing head plug 71 is then run down through the pipe string 100 of FIGURES 2 and 5 and seated in the recess 70 at the top of the body member 30. The head plug 71 may be run down into position in any one of three ways. It may be pumped down the normally empty pipe string 100 by pumping a fluid down above it, or it may be lowered into place by being removably connected to the bottom of a small diameter pipe string that will pass through pipe string 100 with the plug being disconnected either hydraulically or mechanically. Additionally, a plug' may be run into place on a wire line in a collapsed position and set in any manner used for a wire line tool. After the plug 71 has seated, the dogs or locking fingers 73 snap into place. Preferably, a quantity of grease is inserted into the pipe string 100 ahead of the plug 71 so that when the plug 71 is forced into place the grease will be forced down grease channels 79, 80, 154 and 155 (FIGURE 3). The grease from these channels will be forced through grease ports such as 75, 76, 77 and 78 within the wellhead closure to lubricate all areas of the wellhead closure to be protected from corrosion. At this time the space between the bellows unit 9091 and the wellhead closure body 30 is filled.

With the plug 71 in place, a pressure fluid is applied through conduit 156 (FIGURES 4 and 5) to drive piston 112 of the running head 101 upwardly to unlatch the locking dogs 107 and allow the running head 101 together with the pipe string 100 to be withdrawn upwardly to the drilling barge. Removal of the running head 101 allows the bellows unit 90-91 to move upwardly and entirely cover the body member 30. The bellows unit is constructed so that during the injection of grease into the annular space between the outer surface of the body member 30 and the inner surface of the bellows unit any sea water present is replaced by the grease, and during the upward movement of the bellows unit the body of injected grease is rearranged so that it fills the thus-extended annular space to prevent any subsequent entry of sea water.

Rather than employ a plug 71 that fits within a recess in the top of the body member 30 as shown in FIGURE 5, a cap type plug 160 (FIGURE 8) may be used. In order to run the cap plug into place, it would be provided with two or more guide arms 161 by which it could be run into place on guide lines (not shown) in a manner described with regard to the equipment in copending patent application Ser. No. 830,538, filed July 30, 1959. The plug type cap would be provided with several springloaded hold-down dogs 162 adapted to seat in the annular groove 74 of body member 30. Preferably, a guide skirt 163 is provided at the lower end of the plug to guide it into place over the top of the body member 30. A suitable ring of packing material 165 is provided on the inner surface of the cap plug to seal the space between the cap plug 160 and the body member 30. If desired, a second sealing ring 164 may be provided which would seat on the top of the ring 92. The top of the cap plug would be provided with a fishing neck or head 166, preferably covered by a thin rubber-protected cap 167. If it is desired to run the cap 160 into place on the lower end of a pipe string, a running sub or collar 168 may be provided on the top of the cap plug 160 which would be connected to the running pipe or tubing string 169 by means of a shear pin 170. After lowering the cap plug 160 into place on the lower end of the tubing string 169, the cap void is completely filled with an inhibited grease through check valve 171 to seal out any sea water. By a continued downward pressure on the string 169, the pin 170 is sheared, allowing the tubing string to be withdrawn to the surface. While the valves 53 and 54 which control the flow of fluid through conduits 51 and 52 have been illustrated as being positioned within the vertical conduits 33 and 34, it is readily apparent that they may be positioned in the 9 side conduits themselves, or partially in the side conduits and partially in the vertical conduits.

We claim as our invention:

1. In a well installation located underwater at an offshore location comprising well casing means cemented in said well, well tubing means suspended in said casing means, a wellhead assembly closing said casing means and tubing means, apparatus for closing the top of said wellhead assembly and permitting re-entry thereto, said apparatus comprising a body member fixedly secured coaxially to the top of said wellhead assembly in a fluidtight manner, vertical conduit means in said body member, side conduit means through the wall of said body member adapted to be in communication between said vertical conduit means and a pressure-fluid actuated component of said wellhead assembly, valve means in said vertical conduit means for opening and closing said side conduit means, removable closure means normally closing the top of said body member in a fluidtight manner.

2. In a well installation located underwater at an offshore location comprising well casing means cemented in said well, well tubing means suspended in said casing means, a wellhead assembly closing said casing means and tubing means, apparatus for closing the top of said well head assembly and permitting re-entry thereto, said apparatus comprising a cylindrical body member fixedly secured coaxially to the top of said wellhead assembly in a fluidtight manner, vertical conduit means in said body member in communication through said wellhead assembly with the well tubing means, side conduit means through the wall of said body member adapted to be in communication between said vertical conduit means and a "pressure-fluid actuated component of said wellhead assembly, valve means in said vertical conduit means for opening and closing said side conduit means, and removable closure means normally closing the top of said body member in a fluidtight manner.

3. In a well installation located underwater at an offshore location comprising well casing means cemented in said well, dual well tubing means suspended in said casing means, a wellhead assembly closing said casing means and tubing means, apparatus for closing the top of said wellhead assembly and permitting re-entry thereto, said apparatus comprising a cylindrical body member fixedly secured coaxially to the top of said Wellhead assembly in a fluidtight manner, at least two vertical conduits in said body member in communication through said wellhead assembly with the dual well tubing means, side conduit means through the wall of said body member adapted to be in communication between said vertical conduits and a pressure-fluid actuated component of said wellhead assembly, slidable sleeve valve means in said vertical conduits for opening and closing said side conduit means, and remotely removable closure means normally closing the top of said body member in a fluidtight manner.

4. In a well installation located underwater at an offshore location comprising well casing means cemented in said well, well tubing means suspended in said casing means, a wellhead assembly closing said casing means and tubing means, apparatus for closing the top of said wellhead assembly and permitting re-entry thereto, said apparatus comprising a cylindrical body member fixedly secured coaxially to the top of said wellhead assembly in a fluidtight manner, seating means carried by said body member for seating the open bottom end of a vertically positioned marine conductor pipe string thereon, an axially movable protective enclosure surrounding the outer surface of said body member from the top thereof down to at least said seating means, vertical conduit means in said body member in communication through said wellhead assembly with the Well tubing means, side conduit means through the wall of said body member adapted to be in communication between said vertical conduit means and a pressure-fluid actuated component of said wellhead assembly, valve means in said vertical conduit means for opening and closing said side conduit means, and removable closure means normally closing the top of said body member in a fluidtight manner.

5. In -a well installation located underwater at an offshore location comprising well casing means cemented in said well, well tubing means suspended in said casing means, a wellhead assembly closing said casing means and tubing means, apparatus for closing the top of said well-head assembly and permitting re-entry thereto, said apparatus comprising a cylindrical body member fixedly secured coaxially to the top of said wellhead assembly in a fluidtight manner, vertical conduit means in said body member in communication through said wellhead assembly with the well tubing means, side conduit means through the wall of said body member adapted to be in vcommunication between said vertical conduit means and a pressure-fluid actuated component of said wellhead assembly, valve means in said vertical conduit means for opening and closing said side conduit means, remotely removable closure means normally closing the top of said body member in a fluidtight manner, means carried on the outside of said body member for seating and locking thereon the open bottom end of a vertically positioned marine conductor pipe, and a resilient collapsible bellows unit surrounding the outer surface of said body member from the removable closure means thereof down to at least said seating and locking means, said bellows unit being adapted to be forced downwardly to uncover the upper end of said body member.

6. In a well installation located underwater at an olfshore location comprising well casing means cemented in said well, well tubing means suspended in said casing means, a wellhead assembly closing said casing means and tubing means, said wellhead assembly being equipped with pressure-fluid actuated components, apparatus for closing the top of said wellhead assembly and permitting reentry thereto, said apparatus comprising a cylindrical body member fixedly secured coaxially to the top of said wellhead assembly in a fluid-tight manner, vertical conduit means in said body member in communication through said wellhead assembly with the well tubing means, side conduit means through the wall of said body member adapted to be in communication between said vertical conduit means and at least one of said pressure-fluid actuated components of said wellhead assembly, valve means in said vertical conduit means for opening and closing said side conduit means, remotely removable closure means normally closing the top of said body member in a fluidtight manner, and removable tubing plug means above said valve means for closing the vertical conduit means in a fluidtight manner.

7. A method of closing an underwater wellhead assembly having a removable marine conductor pipe string extending to a point above the surface of the water, said wellhead assembly having at least two vertical conduits therein, said method comprising closing said vertical conduits at a point below the top of said wellhead assembly, inserting a quantity of a lubricating material through said pipe string into the top of said wellhead assembly, forcing said lubricating material under pressure into voids within the wellhead assembly, ealing the upper end of said wellhead assembly in a fluid-tight manner, and removing the marine conductor pipe string therefrom.

8. A method of closing an underwater wellhead assembly having a removable marine conductor pipe string extending to a point above the surface of the Water, said wellhead assembly having at least two vertical conduits therein, said method comprising closing said vertical conduits at a point below the top of said wellhead assembly, inserting a quantity of a lubricating material through said pipe string into the top of said wellhead assembly, in serting a plug through said pipe string above said. lubricating material, forcing said plug under pressure against said lubricating material to force said material into voids within the wellhead asembly, sealing the upper end of said wellhead assembly in a fluid-tight manner and removing the marine conductor pipe string therefrom.

9. A method of closing an underwater Wellhead assembly having a removable marine conductor pipe string extending to a point above the surface of the water, said wellhead assembly having at least two vertical conduits therein, said method comprising closing said vertical conduits with valve means at a point below the top of said wellhead assembly, inserting a quantity of a lubricating material through said pipe string, inserting a wellhead sealing plug in said pipe string above said lubricating material, pumping said plug under pressure through said pipe string and against said lubricating material to force said material into voids within the wellhead assembly, sealing the upper end of said wellhead assembly in a fluid-tight manner by seating said plug therein, and removing the marine conductor pipe string therefrom.

10. A method of closing an underwater wellhead assembly having a removable marine conductor pipe string extending to a point above the surface of the water, said wellhead assembly having at least two vertical conduits therein, said method comprising closing said vertical conduits with valve means and plug means at a point below the top of said wellhead assembly, inserting a quantity of a fluid sealing and lubricating material through said pipe string, inserting a wellhead sealing plug in said pipe string above said sealing and lubricating material, pumping a fluid through said pipe string in back of said plug to force said plug under pressure against said sealing and lubricating material to force said material into voids within the wellhead assembly, sealing the upper end of said wellhead assembly in a fluid-tight manner by seating said plug therein, and removing the marine conductor pipe string therefrom.

11. The method of closing an underwater well installation having casing means cemented into a well, tubing means suspended in the casing, 'a wellhead assembly enclosing the casing means and the tubing means, and, connected above the wellhead assembly, an open-topped cylindrical body member which is traversed by conduits leading into communication with the tubing means and the wellhead assembly, the body member being provided with external engaging-surface for intimately engaging cooperating surfaces on units which are telescoped over the body member, said method comprising mounting a flexible, cylindrical sheath containing a resilient, longitudinally-extending member around the cylindrical body member in sliding engagement, so that in substantially relaxed condition the sheath covers the external engaging-surfaces on the body member, providing a conduit extending from the upper portion of the body member interior into the annular space between the sheath and the body member during the closing in of the underwater well installation, extending a marine conductor pipe from a point above the water surface into a position in which lower portions of the marine conductor telescope over the body member and longitudinally-compress the flexible sheath and surfaces on the marine conductor intimately engage with the external engaging-surfaces on the body member, closing the conduits extending from the interior of the body member into communication with the tubing means and the wellhead assembly, pumping grease through the marine conductor and the body member into the annular space between the body member and the flexible sheath; closing the opening into the body member, and, removing the marine conductor, allowing the flexible sheath to longitudinally-extend to its substantially relaxed condition covering the external engaging surfaces on the body member.

12. In a well installation located underwater at an offshore location comprising well casing means extending into the well drilled in the ocean floor, a wellhead assembly closing said casing means, apparatus for closing the top of said wellhead assembly, said apparatus comprising a body member fixedly secured to the top of the wellhead assembly in a fluidtight manner, vertical conduit means in said body member, side conduit means through the wall of said body member in communication with said vertical conduit means, valve means carried by said body member for opening and closing said side conduit, and removable closure means normally closing the top of said body member in a fluidtight manner.

13. In a well installation located underwater at an offshore location comprising well casing means and well tubing means extending into the well drilled in the ocean floor with a wellhead assembly closing said casing means, apparatus for closing the top of said wellhead assembly, said apparatus comprising a body member fixedly secured to the top of the wellhead assembly in a fluidtight manner, fluid flow-line means in said wellhead assembly in communication at one end with well tubing means in said well, pressure-fluid actuated flow control valve means in said fluid flow-line means, vertical conduit means in said body member, side conduit means through the wall of said body member in communication with said vertical conduit means at one end and with at least one of said pressure-fluid actuated flow control valve means at the other end for actuating said valve means, and removable closure means normally closing the top of said body member in a fluidtight manner.

14. The apparatus of claim 13 wherein a portion of said body member is provided with latching means on the outer surface thereof for receiving and cooperating with a wellhead connector carried at the lower end of a pipe string and lowerable into telescopic arrangement with said body member.

15. The apparatus of claim 13 wherein a portion of the outer surface of said body member forms sealing surface means adapted to receive thereagainst in a fluidtight manner an annular sealing element carried by a wellhead connector at the lower end of a pipe string.

16. The apparatus of claim 15 including retractible axially-movable sleeve means normally covering said sealing surface means.

17. A method of establishing communication with a tubing string of an underwater wellhead assembly where the tubing string is normally closed by a valve actuatable by pressure to an open position, said method comprising the steps of (a) opening the top of the wellhead assembly (b) extending down through a body of water from a position thereabove, a tubing string,

(0) inserting said tubing string through said open top of said wellhead assembly and placing it in communication with the upper end of a tubing of said wellhead assembly,

(d) extending conduit means down through said body of water from said position thereabove,

(e) placing the lower end of said conduit means through the open end of said wellhead assembly and in operative communication with said valve to actuate said valve, and

(f) applying a pressure fluid through said conduit means to open said valve in the tubing of said wellhead assembly to bring it into communication with said tubing string.

18. The method of claim 17 including the step of latching the lower end of said tubing string to said wellhead assembly.

19. The method of claim 17 including the prior steps of (a) extending a marine conductor pipe down through the body of water to a wellhead assembly,

(b) positioning the lower end of the conductor pipe on the top of said wellhead assembly, and

(c) sealing the lower end of the conductor pipe in a fluidtight manner to the wellhead assembly.

20. In a well installation located underwater at an offshore location comprising well casing means cemented in said well, well tubing means suspended in said casing means, a Wellhead assembly closing said casing means and tubing means, apparatus for closing the top of said wellhead assembly and permitting re-entry thereto, said apparatus comprising a body member fixedly secured coaxially to the top of said wellhead assembly in a fluid tight manner, a portion of the outer surface of said body member forming sealing surface means adapted to receive thereagainst in a fluidtight manner an annular sealing element, vertical conduit means in said body member, side conduit means through the wall of said body member adapted to be in communication between said vertical conduit means and at least one of said pressure-fluid actuated components of said wellhead assembly, removable closure means normally closing the top of said body member in a flnidtight manner.

21. A latch head connectable to a plurality of flow conductors for use with well devices having locking means and sealing means including: a body having a plurality of longitudinal bores, said body having means at one end of each of said longitudinal bores for receiving and connecting a well flow conductor thereto with the well flow conductors opening into said bores when said latch head is connected to the flow conductors, each of said bores being provided with internal groove latch means engageable by locking means of well devices for releasably securing well devices in said bore; and an internal annular seal surface provided in each of said bores engageable by sealing means of well devices, said latch head body being provided with an external shoulder latch means engageable by running and pulling tools whereby the latch head and the flow conductors connected therewith may be lowered and raised by said tools.

22. In combination with the latch head of claim 21 means for connecting an operating member and flow conduit with said latch head including: a tubular body telescopable relative to said latch head and having a first means engageable with said external shoulder latch means of said latch head for releasably securing said tubular body to said latch head; lock means carried by said tubular body and movable between a first locking position wherein said first means is engaged and locked by said lock means against movement out of engagement with said external shoulder latch means and a second position wherein said lock means is out of locking engagement with said first means and said first means is free to move out of engagement with said external shoulder latch means upon movement of the tubular body from said latch head; and means operable from a remote point for moving said lock means between said first position and said second position.

23. In combination with the latch head of claim 21 means for connecting an operating member with said latch head and including: a tubular body telescopable relative to said latch head and having first means engageable with said external" shoulder latch means of said latch head for releasably securing said tubular body-to said head; lock means carried by said tubular body and movable between a first locking position wherein said first means is engaged and locked by said lock means against movement out of engagement with said external shoulder latch means and a second position wherein said lock means is out of locking engagement with said first means and said first means is free to move out of engagement with said external shoulder latch means upon movement of the tubular body from said latch head; means operable from a remote point for moving said lock means between said first position and said second position and a conduit secured to said tubular body and communicating with said bores when said tool is secured to said latch head.

24. A latch head connectable to a plurality of flow conductors for use with well devices having locking means and sealing means including: a body having a plurality of laterally spaced separate longitudinal bores, said body having means at one end of each of said separate longitudinal bores for receiving and connecting a well flow conductor thereto with the flow conductors opening into said bores when said latch head is connected to the flow conductors, each of said bores being provided with internal shoulder and groove latch means engageable by locking means of well devices for releasably securing well devices in said bore; and an internal annular seal surface provided in each of said bores adjacent said latch means and engageable by sealing means of well devices, said latch head body being provided with an external annular shoulder and groove latch means engageable by running and pulling tools whereby the latch head and its flow conductor may be lowered and raised by said tools, said latch head body having an upwardly facing stop shoulder engageable by running and pulling tools to limit downward movement of the running and pulling tools relative to said latch head.

25. A latch head connectable to a plurality of flow conductors for use with well devices having locking means and sealing means including: a body having a plurality of separate laterally spaced longitudinal bores, said body having means thereon at one end of each of said longitudinal bores for receiving and connecting a well flow conductor thereto with the flow conductors opening into said bores when said latch head is connected to the flow conductors, each of said bores being provided with internal annular groove and shoulder latch means engageable by locking means of well devices for releasably securing well devices in said bore; and an internal annular seal surface provided in each of said bores engageable by a sealing means of the well device, said latch head body being provided with an external shoulder and groove latch means engageable by running and pulling tools whereby the latch head and the flow conductors connected thereto may be lowered and raised by said tools, said latch head body being provided on its exterior with orienting means engageable with running and pulling tools for orienting said running tools relative to said bores.

26. A latch head connectable to a plurality of flow conductors for use with well devices having locking means and sealing means including: a body having a plurality of laterally spaced separate longitudinal bores, said body having means at one end of each of said bores for receiving and connecting a well flow conductor thereto with the flow conductors opening into said bores when said latch head is connected to the flow conductors, each of said bores being provided with internal annular groove and shoulder latch means engageable by locking means of well devices for releasably securing well devices in said bore; and an internal annular seal surface provided in each of said bores adjacent the latch means thereof engageable by sealing means of well devices, said latch head having an upper bore providing an internal annular seal surface above said longitudinal bores, said longitudinal bores opening upwardly into said upper bore and downwardly to the exterior of said body.

27. A latch head connectable to a plurality of flow conductors for use with well devices having locking means and sealing means including: a body having a plurality of laterally spaced separate longitudinal bores, said body having means at one end of each of said bores for receiving and connecting a well flow conductor thereto with the flow conductors opening into said bores when said latch head is connected to a well flow conductor, each of said bores being provided with an internal annular groove and an upwardly facing stop shoulder therein spaced longitudinally from said groove and providing with said groove latch means engageable by locking means of well devices for releasably securing well devices in said bore; and an internal annular seal surface provided in each of said bores adjacent the latch means thereof engageable by sealing means of well devices, said latch head having an upper bore providing an internal annular seal surface above said longitudinal bores, said longitudinal bores opening upwardly into said upper bore and downwardly means.

References Cited UNITED STATES PATENTS Brown 166-87 Rector 166-87 Focht et a1. 166-46 Reistle 166-46 16 2,889,886 6/1959 Gould 166-89 2,906,500 9/1959 Knapp et a1. 166-75 2,927,643 3/ 1960 Dellinger 166-75 CHARLES E. OCONNELL, Primary Examiner R. E. FAVREAU, Assistant Examiner US. Cl. X.R. 166-87 

1. IN A WELL INSTALLATION LOCATED UNDERWATER AT AN OFFSHORE LOCATION COMPRISING WELL CASING MEANS CEMENTED IN SAID WELL, WELL TUBING MEANS SUSPENDED IN SAID CASING MEANS, A WELLHEAD ASSEMBLY CLOSING SAID CASING MEANS AND TUBING MEANS, APPARATUS FOR CLOSING THE TOP OF SAID WELLHEAD ASSEMBLY AND PERMITTING RE-ENTRY THERETO, SAID APPARATUS COMPRISING A BODY MEMBER FIXEDLY SECURED COAXIALLY TO THE TOP OF SAID WELLHEAD ASSEMBLY IN A FLUIDTIGHT MANNER, VERTICAL CONDUIT MEANS IN SAID BODY MEM- 